Person: Heß, Michael
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Veröffentlichung Analysis of archive samples of spring and winter barley support an increase in individual Fusarium species in Bavarian barley grain over the last decades(2019) Hofer, Katharina; Heß, Michael; Hückelhoven, RalphA broad range of different Fusarium (F.) species is associated with Fusarium head blight (FHB) on barley and the corresponding negative effects in downstream processing of barley grain in food and feed production. Previous studies highlight the significance of the wheat-relevant and well-studied species F. graminearum as well as less prominent species including F. culmorum, F. avenaceum, F. tricinctum, F. langsethiae, F. sporotrichioides, F. poae, and others. In this context, prevalent climate and cultivation conditions were shown to determine disease severity as well as dominance of certain species within the Fusarium pathogen complex. To gain further insight into possible historic developments of FHB, the annual occurrence of currently relevant Fusarium species was analyzed in Bavarian archive samples of winter (from 1958 to 2010) and spring barley (from 1965 to 2010) using species-specific quantitative polymerase chain reaction. Although DNA contents varied between samples of individual years, data suggest a general increase in Fusarium incidence, particularly in spring barley. Comparing pathogen complexes, we observed not only continuous dominance of F. graminearum in winter barley, but also an increasing relevance of this species in spring barley. The rising Fusarium incidence over time generally coincides with climate change related factors like increasing temperatures. However, it may furthermore be linked to changing cultivation methods and intensified maize production. This study therefore exhibits the dynamic complexity of barley grain contamination with Fusarium spp., which should be taken into account for future disease management. Quelle: https://link.springer.comVeröffentlichung Influence of Fusarium avenaceum infections on barley malt: Monitoring changes in the albumin fraction of barley during the malting process(2019) Geißinger, Cajetan; Whitehead, Iain; Heß, Michael; Hofer, KatharinaFusarium spp. are ubiquitous field pathogens, which are known to affect quality characteristics of cereals. Infections with Fusarium pathogens in brewing cereals are problematic and augur for a poor malt quality. The negative effects of Fusarium infections are various. Besides causing agronomic losses, kernel discoloration, and the production of several mycotoxins, Fusarium spp. are known to enhance the proteolytic activity of infected barley malt. Enhanced proteolysis can be observed in higher values in free amino nitrogen (FAN) as well as in soluble nitrogen. Previous studies showed that, in recent crop years, the predominant Fusarium spp. detected in European malt was F. avenaceum. This study focuses on the changes in the albumin fraction during the malting process of barley samples artificially infected with F. avenaceum in comparison to uninfected control samples. The barley samples were grown under controlled conditions in a greenhouse, and two different sample types were studied: One was not infected with Fusarium spores whereas the other sample was inoculated during anthesis with a spore suspension of F. avenaceum. Malting trials were carried out in a micromalting facility under defined conditions. To monitor the changes in protein profiles due to Fusarium infection, samples were analyzed at different stages of the malting process: barley (raw grain), poststeeping, postgermination, and postkilning. To evaluate the changes in the protein composition, different fractionation techniques (Osborne fractionation, isoelectric focusing, and capillary gel electrophoresis) were utilized. The albumins of the Osborne fractionation were further analyzed as they represent the main metabolically active proteins. Protein maps of the different malting steps were plotted with a custom-programmed visualization tool for comparing the infected and uninfected samples at each malting step. The results elucidate the changes in the albumin fraction during the malting process and reveal the influence of Fusarium infection on the albumin composition of barley, barley malt, and the intermediate products of malting. © 2019 Elsevier B.V. All rights reserved.Veröffentlichung Ramularia leaf spot disease of barley is highly host genotype-dependent and suppressed by continuous drought stress in the field(2020) Hoheneder, Felix; Hofer, Katharina; Heß, Michael; Groth, JenniferSince the 1980s, Ramularia leaf spot (RLS) is an emerging barley disease worldwide. The control of RLS is increasingly aggravated by a recent decline in fungicide efficacy and a lack of RLS-resistant cultivars. Furthermore, climate change increases drought periods in Europe, enhances variable weather conditions, and thus will have an impact on severity of plant diseases. Hence, identification of RLS-resistant cultivars and understanding of disease progression under abiotic stress are important aims in integrated disease management under climate change. In the present study, we evaluated quantitative RLS resistance of 15 spring barley genotypes under drought, controlled irrigation and field conditions between 2016 and 2019 and monitored microclimatic conditions within the canopy. We identified genotypes that show robust quantitative resistance to RLS in different field environments. Our findings suggest that long-lasting drought periods create unfavourable conditions for the disease and supports that the extent and duration of leaf wetness is a key factor for RLS epidemics. © The Author(s) 2020Veröffentlichung Ramularia leaf spot disease of barley is highly host genotype-dependent and suppressed by continuous drought stress in the field(2021) Hoheneder, Felix; Hofer, Katharina; Heß, Michael; Groth, JenniferSince the 1980s, Ramularia leaf spot (RLS) is an emerging barley disease worldwide. The control of RLS is increasingly aggravated by a recent decline in fungicide efficacy and a lack of RLS-resistant cultivars. Furthermore, climate change increases drought periods in Europe, enhances variable weather conditions, and thus will have an impact on severity of plant diseases. Hence, identification of RLS-resistant cultivars and understanding of disease progression under abiotic stress are important aims in integrated disease management under climate change. In the present study, we evaluated quantitative RLS resistance of 15 spring barley genotypes under drought, controlled irrigation and field conditions between 2016 and 2019 and monitored microclimatic conditions within the canopy. We identified genotypes that show robust quantitative resistance to RLS in different field environments. Our findings suggest that long-lasting drought periods create unfavourable conditions for the disease and supports that the extent and duration of leaf wetness is a key factor for RLS epidemics. © The Author(s) 2021Veröffentlichung Host genotype and weather effects on fusarium head blight severity and mycotoxin load in spring barley(2022) Hoheneder, Felix; Biehl, Eva Maria; Heß, Michael; Hofer, KatharinaEpidemiology of Fusarium Head Blight (FHB) of spring barley is relatively little understood. In a five-year study, we assessed quantitative resistance to FHB in an assortment of 17 spring barley genotypes in the field in southern Germany. To this end, we used soil and spray inoculation of plants with F. culmorum and F. avenaceum. This increased disease pressure and provoked genotypic differentiation. To normalize effects of variable weather conditions across consecutive seasons, we used a disease ranking of the genotypes based on quantification of fungal DNA contents and multiple Fusarium toxins in harvested grain. Together, this allowed for assessment of stable quantitative FHB resistance of barley in several genotypes. Fungal DNA contents were positively associated with species-specific Fusarium toxins in single years and over several years in plots with soil inoculation. In those plots, plant height limited FHB; however, this was not observed after spray inoculation. A multiple linear regression model of recorded weather parameter and fungal DNA contents over five years identified time periods during the reproductive phase of barley, in which weather strongly influenced fungal colonization measured in mature barley grain. Environmental conditions before heading and late after anthesis showed strongest associations with F. culmorum DNA in all genotypes, whereas for F. avenaceum, this was less consistent where we observed weather-dependent associations, depending on the genotype. Based on this study, we discuss aspects of practical resistance breeding in barley relevant to improve quantitative resistance to FHB and associated mycotoxin contaminations. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.